Lipid-Extruded PEGylated Liposomes of Repurposed Sorafenib for Triple-Negative Breast Cancer: A Mechanistically Enhanced Nanoplatform with Improved In Vivo Pharmacokinetics and Targeted Biodistribution.

Triple-negative breast cancer (TNBC) presents a therapeutic challenge due to its complex pathology and limited treatment options. Addressing this challenge, our study focuses on the effectiveness of combination therapy, which has recently become a critical strategy in cancer treatment, improving therapeutic outcomes and combating drug resistance and metastasis. We explored a novel combination therapy employing Benzyl isothiocyanate (BITC) and Sorafenib (SOR) and their nanoformulation, aiming to enhance therapeutic outcomes against TNBC. Through a series of in vitro assays, we assessed the cytotoxic effects of BITC and SOR, both free and encapsulated. The BITC-SOR-loaded nanoparticles (NPs) were synthesized using an amphiphilic copolymer, which demonstrated a uniform spherical morphology and favorable size distribution. The encapsulation efficiencies, as well as the sustained release profiles at varied pH levels, were quantified, revealing distinct kinetics that were well-modeled by the Korsmeyer-Peppas equation. The NP delivery system showed a marked dose-dependent cytotoxicity towards TNBC cells, with an IC50 of 7.8 μM for MDA-MB-231 cells, indicating improved efficacy over free drugs, while exhibiting minimal toxicity toward normal breast cells. Furthermore, the NPs significantly inhibited cell migration and invasion in TNBC models, surpassing the effects of free drugs. These findings underscore the potential of BITC-SOR-NPs as a promising therapeutic approach for TNBC, offering targeted delivery while minimizing systemic toxicity.

Background: Triple-negative (negative for human epidermal growth factor receptor 2 [HER2] and estrogen and progesterone receptors) breast cancer (TNBC) is the breast cancer subtype with the worst prognosis. It represents approximately 15% -20% of all breast cancer cases. BRCA 1 and /or BRAC 2 mutation accounts for about 15% of all TNBC and remains poor outcomes for such patients. TORCHLIGHT trial is a randomized, double-blinded, phase 3 study assesses the efficacy and safety of toripalimab (programmed cell death-1 inhibitor) combined with nab-paclitaxel (nab-P) as a first-line treatment for patients diagnosed with metastatic or recurrent TNBC. The (progression-free survival) PFS and (overall survival) OS analysis, showed a significant improvement in PD-L1 positive (CPS ≥ 1) tumors. Phase III OlympiAD study has established the efficacy of Poly ADP-ribose polymerase inhibitors (PARPi) olaparib in patients with germline BRCA gene mutation (gBRCAm) and human epidermal growth factor receptor 2 (HER2) negative metastatic breast cancer. Mefuparib hydrochloride (CVL218) is a second generation of PARPi with low hematological toxicity and the ability to cross the blood-brain barrier. The major purpose of this study is to explore the RP2D, efficacy and safety of CVL218 combined with PD-1 inhibitors and paclitaxel nanoparticle albumin-bound in patients with TNBC who have failed previous first-line treatment. The second endpoint of this study is to analyze the efficacy of each subgroup according to PD-L1 expression and HRD (Homologous Recombination Deficiency) mutation status. Methods: This open- labeled, phase Ib/II clinical study was conducted in China. In phase Ib, the “3+3” principle is used to explore the RP2D of CVL218. Two dose escalation of CVL218 were preset, which are 500mg twice daily (BID) and 700mg BID. CVL218 administered orally in combination with toripalimab 240 mg on Day 1 of every 21-day cycle and paclitaxel nanoparticle albumin-bound 125 mg/m2 on Day 1 of every 21-day cycle. The first cycle (21 days) after administration was also defined as the DLT (dose-limiting toxicity) observation period. At last, no DLT was observed in the 3 evaluable subjects in the CVL218 500 mg BID dose group, and DLT was observed in 2 evaluable subjects in the 700 mg BID dose group, including creatinine increased and aspartate aminotransferase, Alanine aminotransferase increased. Therefore, the RP2D was determined as 500 mg BID. Patients in phase II cohort A were advanced TNBC with either CPS ≥ 1 or HRD gene pathogenic variants. All these patients received CVL218 (500mg BID) + toripalimab (240 mg) + paclitaxel nanoparticle albumin-bound (125 mg/m2, ). Results: From July 2023 to 15 July 2024 data, a total of 6 subjects were enrolled in Phase Ib and 5 subjects were enrolled in Phase II. The median age of the 11 subjects was 55.2 years. In phase Ib, The RP2D of CVL218 was identified as 500 mg BID. The preliminary efficacy was perfomed every 6 weeks in the first half a year and then once every 12 weeks thereafter in both phase I and II according to RECISTv 1.1. Among 11 patients, ORR (Objective Respond Rate) was 72.7% (8 PR, 2 SD), and DCR (Disease Control Rate) was 90.9%. The most common Grade 3 or higher treatment-related AEs (TRAEs) were hepatic function injury (2.6%), adynamia (1.8%), creatinine increased (0.8%), neutrophils decreased (0.8%), white blood cell decreased (0.8%), exanthema (0.8%), and peripheral sensory nerve disorder (0.8%), No Grade 5 TRAE. A total of 9 treatment-related SAEs in 6 patients (54.5%) were observed, including 2 aspartate aminotransferase increased, 2 alanine aminotransferase increased, 1 creatinine increased, 1 liver function injury, 1 adynamia, 1 neutrophils decreased, 1 fever, and 1 ventricular premature beats. All these SAEs recovered after symptomatic treatment. Conclusion: Mefuparib Hydrochloride(CVL218) combined with PD-1 and chemotherapy appears to be well tolerated and has preliminary efficacy in TNBC patients. In this phase II study, stratified analyses will be conducted for PD-L1 expression and HRD status. In patients with BRCA 1 and /or BRAC 2 mutation TNBC, this CVL218 combination therapy is expected to further break through the clinical treatment effect. Citation Format: Jian Zhang, Rujiao Liu. A phase Ib/II study of PARPi Mefuparib Hydrochloride (CVL218) in combination with PD-1 inhibitor plus chemotherapy in metastatic or recurrent triple-negative breast cancer (TNBC) [abstract]. In: Proceedings of the San Antonio Breast Cancer Symposium 2024; 2024 Dec 10-13; San Antonio, TX. Philadelphia (PA): AACR; Clin Cancer Res 2025;31(12 Suppl):Abstract nr P4-04-31.

Background CDK4/6 inhibitors may trigger anti-tumour immunity, both through tumour cell intrinsic and extrinsic mechanisms, which can be enhanced by immune checkpoint blockade in pre-clinical studies. Although most triple negative breast cancers (TNBC) are resistant to CDK4/6 inhibition, palbociclib (palbo) has activity in pre-clinical models of the luminal androgen receptor (LAR) subtype. Here we report the dose finding phase Ib cohort A of the PAveMenT trial combining avelumab and palbociclib Methods The PAveMenT phase 1b trial consists of a dose finding phase (cohort A), to be followed by an expansion in androgen receptor positive (AR+) TNBC (Cohort B). The phase 1B phase investigated palbo dosing schedules (75mg intermittent dosing (ID), 100mg continuous dosing (CD) and 125mg ID) in combination with the anti-PD-L1 antibody, avelumab 10mg/kg 2-weekly (cohort A) to determine the optimal schedule for cohort B. The CD dose-level was pre-specified as the preferred schedule if tolerated, due to the proliferative nature of TNBC and potential for tumour re-growth with ID. Patients with previously treated advanced breast cancer (ABC) of any histology with measurable disease and adequate organ function, who had not received prior immunotherapy or CDK4/6 inhibitors or more than 2 lines of chemotherapy for ABC, were eligible for cohort A. Dose-limiting toxicities (DLTs) were defined as Grade(G) 4 neutropenia, complicated G3 neutropenia or G4 thrombocytopenia, or ≥G3 immune toxicity during cycle 1. AR staining of ≥10% using the SP107 antibody (Ventana) was considered AR+. PD-L1 was evaluated using CC23 Pharma Dx antibody (DAKO) and PD-L1 positive defined as CPS score of ≥10%. Results Fourteen patients were recruited to Part A, all female, 12 with TNBC, two with ER positive/HER2 negative ABC, median age 53.5 years. Three evaluable patients received palbo 75mg/day ID without DLTs, therefore two further dose levels were opened in parallel. Three evaluable patients received palbo 125mg/day ID without DLTs. Due to a DLT of fever with G3 neutropenia in one of 3 patients receiving palbo 100mg CD, 3 further evaluable patients received 100mg CD without DLTs. Two patients were not evaluable for DLTs having not received a full cycle of treatment so were replaced. One case of grade 3 colitis and one case of grade 2 hypothyroidism (both 100mg CD) occurred outside the DLT period. Amongst 12 patients with TNBC, metastatic tissue was available for 11, archival breast tissue for one. Four of 12 patients were AR+. Five of 10 TNBC patients with sufficient tissue were PD-L1 positive, all of whom had previously tested negative with the SP142 antibody (Ventana). One of the 5 PD-L1+ and 2/5 PD-L1 negative TNBC cases were also AR+. TNBC patients received a median of 2 cycles of treatment (range 1-17). Both ER+ patients were AR+ and PD-L1 negative; one progressed after 4 cycles, the other remains on treatment at 12 cycles. The 100mg CD schedule was selected for cohort B. Conclusions All schedules were tolerable, with activity observed in patients with both ER positive and TNBC cancers. Cohort B of the study is open to recruitment for patients with AR+ TNBC. NCT04360941. Citation Format: Alicia F. Okines, Houman Moghadam, Laura Sparks, Kabir Mohammed, Kathryn Dunne, Ashutosh Nerurkar, Peter Osin, Claire Swift, Ruth Sardinha, Nicholas Turner. Results from a dose escalation phase 1b study of palbociclib and avelumab in advanced breast cancer in the PAveMenT Trial [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P4-01-02.

Carbon nanoparticles-Fe(II) complex combined with sorafenib for ferroptosis-induced antitumor effects in triple-negative breast cancer.

e15047 Background: Triple negative breast cancer (TNBC) accounts for about 10-15% of all breast cancers and differ from other types of invasive breast cancers in that they grow and spread faster. TNBCs have limited treatment options and a worse prognosis. Therapy with anthracyclines considered to be one of the most effective agents in the treatment. Unfortunately, resistance to anthracycline therapy is very common due to drug efflux mediated by overexpression of ABC transporter. Pirarubicin (PIRA), an analogue of doxorubicin (DOX), is approved in Japan, Korea and China and is shown to be less cardiotoxic than DOX. Recent studies suggest that cancer stem cells (CSCs) play an important role in tumorigenesis and biology of TNBC. Targeting CSCs may be a promising, novel strategy for the treatment of this aggressive disease. Recent studies have shown that salinomycin (SAL) preferentially targets the viability of CSCs. Methods: SAL and PIRA were co-encapsulated in polylactic acid (PLA)-based block copolymeric nanoparticles (NPs) to efficiently co-deliver these agents to treat TNBC cells. Results: Generated SAL-PIRA co-encapsulated dual drug-loaded NPs showed an average diameter of 110 ± 7 nm, zeta potential of -12.5 mV and PDI of less than 0.25. Both of these anti-cancer agents showed slow and sustained release profile in non-physiological buffer (PBS, pH 7.4) from these dual drug-encapsulated NPs. Additionally, multiple ratios (PIRA:SAL = 3:1, 1:1, 1:3) were encapsulated to generate diverse dual drug-loaded NPs. The results demonstrate that, in contrast to 1:1 and 3:1, treatment of TNBC cells with 1:3 ratio of PIRA:SAL dual drug-loaded NPs, was associated with significant inhibition of growth in vitro in multiple TNBC cell lines. Interestingly, PIRA:SAL (1:3) was synergistic as compared to either SAL- or PIRA single drug-loaded NPs. The IC50 of PIRA and SAL in single drug-encapsulated NPs is 150 nM and 700 nM respectively in MDA-MB-468. Importantly, the IC50 of PIRA in dual drug-encapsulated NPs dropped down to 30 nM (5-fold). Similar results were obtained in SUM-149 TNBC cell line. Studies are underway to evaluate in vivo biological activity of PIRA:SAL (1:3) on tumor growth in a TNBC xenograft mice model. Conclusions: These results demonstrate that a novel dual drug-loaded NP formulation of PIRA and SAL in a unique ratio of 1:3 represents an approach for successful targeting of CSCs and bulk tumor cells in TNBC and potentially other cancer types.

Chemoresistance and metastasis are the main causes of death in triple negative breast cancer (TNBC) patients and have been linked to a subpopulation of cancer stem cells (CSCs) with self-renewal and tumor-initiating properties. We have previously demonstrated that nitric oxide synthase (NOS) promotes tumor relapse and metastasis through modulation of CSC self-renewal properties. Importantly, NOS inhibition with the pan-NOS inhibitor NG-monmethyl-L-arginine (L-NMMA) reduced tumor growth and CSC renewal and tumor-initiating capacity and improved chemosensitivity to docetaxel in mouse models of TNBC. Based on these findings, we are conducting an ongoing Phase Ib trial of proprietary L-NMMA plus docetaxel in refractory locally advanced or metastatic TNBC (NCT02834403). The primary endpoint will be the maximum tolerated dose (MTD) of the L-NMMA and docetaxel combination. The study will be conducted in two stages. Stage 1 will determine the MTD of L-NMMA when combined with 75 mg/m2 docetaxel, and stage 2 will determine the MTD of L-NMMA when combined with 60 mg/m2 docetaxel. Five dose levels of L-NMMA (5, 7.5, 10, 12.5, and 15 mg/kg) will be investigated in stage 1, with 7.5 mg/kg as the starting dose. In stage 2, the starting dose of L-NMMA will be one dose level above the MTD determined in stage 1. As patients are accrued in both stages, a standard Bayesian model averaging continual reassessment method approach will be used to determine L-NMMA escalation/de-escalation. L-NMMA (Days 1−5 of each cycle) and docetaxel (Day 1 of each cycle) will be administered for six 21-day cycles. The major inclusion criteria will be female patients with pathologically advanced (progressive disease or refractory to 3 cycles of standard chemotherapy) or metastatic (any line) TNBC, Eastern Cooperative Oncology Group performance status of ≤2, life expectancy ≥6 months, and adequate organ function. Major exclusion criteria include any cardiac history and pregnancy/breastfeeding. Correlative studies will include evaluation of the pharmacokinetics and pharmacodynamics of the L-NMMA and docetaxel combination and tissue and blood-based markers of treatment response. Notably, analysis of RPL39 and MLF2 in plasma cell-free DNA samples will be performed. We have previously identified these genes as part of a chemotherapy resistance signature derived from breast cancer patient biopsies and have found that they promote breast CSC self-renewal, treatment resistance, and lung metastasis through NOS upregulation. Study enrollment began in August 2016. Two patients have been enrolled; both patients received 7.5 mg/kg L-NMMA and 75 mg/m2 docetaxel and no dose-limiting toxicities have been observed to date. L-NMMA Plus Docetaxel for refractory TNBC Citation Format: Jenny Chang, Angel Rodriguez, Joe Ensor. Clinical phase Ib trial of L-NMMA plus docetaxel in the treatment of refractory locally advanced or metastatic triple negative breast cancer patients [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr CT037. doi:10.1158/1538-7445.AM2017-CT037

Background: Metastatic triple-negative breast cancer (TNBC) is an aggressive and heterogeneous cancer with limited therapeutic options. PARP inhibitors (PARPi) are approved to treat breast cancer harboring germline BRCA1/2 (gBRCA1/2) mutations and have not shown efficacy in homologous recombination DNA repair (HRR) proficient tumors. In pre-clinical models, the BET inhibitor (BETi) ZEN003694 sensitizes wild-type BRCA1/2 tumors to PARPi through downregulation of HRR gene expression, providing a rationale for combination therapy. We report initial results from a Ph 1b/2 trial evaluating the combination of ZEN003694 and the PARPi, talazoparib, in TNBC patients without gBRCA1/2 mutations. Methods: A Ph 1b dose-finding segment will be followed by a single-arm Ph 2 Simon 2-stage segment. Ph 1b evaluated several dose combinations of ZEN003694 and talazoparib, with safety and recommended Ph 2 dose (RP2D) as primary endpoints and pharmacokinetics (PK), pharmacodynamics (PD), and clinical benefit rate (CBR = Objective response rate (ORR) + stable disease > 4 months) as secondary endpoints. The Ph 2 segment has CBR as the primary endpoint and progression free survival (PFS) and duration of response as secondary endpoints. Eligibility criteria included TNBC (ER/PR < 10% and not a candidate for endocrine therapy), HER2-, wild-type gBRCA1/2, and > 1 prior chemotherapy regimen for metastatic disease. Patients were dosed daily in continuous 28-day cycles until disease progression or unacceptable toxicity. Dose limiting toxicity (DLT) period was one cycle. Adverse events (AE), PK, and PD in whole blood and tissue biopsies were assessed. Response endpoints were assessed per RECIST 1.1 every 2 cycles. Results: Findings of the Ph 1b are reported. 15 patients with a median 3 lines of prior therapy in the metastatic setting were enrolled in 3 dose-finding cohorts. RP2D was determined to be 48mg ZEN003694 plus 0.75mg talazoparib. Across the cohorts, the most common AE was thrombocytopenia (TCP) (73%) with 53% G3/4 (Table 1). G4 TCP was the DLT and 1 DLT patient required a platelet transfusion. TCP could be managed to G1/2 levels with intermittent dose holds and reductions. Other G1/2 AEs included fatigue, anorexia, neutropenia, nausea, dysgeusia, and photophobia. Dose intensity analysis showed average daily doses of ZEN003694 and talazoparib could be maintained above 40mg and 0.5mg, respectively, over 4 cycles. Exposures of ZEN003694 and talazoparib were dose proportional with no drug-drug PK interactions. At RP2D, PD assessment by a whole blood mRNA assay for BET-dependent genes demonstrated robust down-regulation of CCR1, IL1RN, and IL8 to < 50% of baseline for > 8 h. Expression of HRR genes, RAD51 and BRCA1, in whole blood also decreased for > 8 h. Analysis of an on-treatment biopsy showed robust and durable BET target modulation assessed by comparing RNA sequence data with a reference BET dependent signature. Across the 3 cohorts, ORR by Investigator was 38% (5/13), including 1 CR and 4 PRs, and CBR was 57% (8/14). 6 of the 15 patients are ongoing as of data analysis date (2-9 cycles), with 1 patient responding for > 6 months. Conclusions: Combination of ZEN003694 and talazoparib demonstrated anti-cancer activity in pretreated metastatic TNBC patients without gBRCA1/2 mutations. TCP is frequent but manageable with dose adjustments. PK is predictable, and PD data show meaningful target engagement. The Ph 2 part of the trial is currently ongoing. Grade 3/4 Adverse EventsCohort 1(1mg talazoparib + 48mg ZEN003694)N=6Cohort 2(0.75 mg talazoparib + 48mg ZEN003694)N=6Cohort 3(1mg talazoparib + 36mg ZEN003694)N=3Thrombocytopenia3 (G3), 2 (G4, DLT)1 (G3), 1 (G4, DLT)1 (G3)Diarrhea1 (G3)00Neutropenia01 (G3)0 Citation Format: Philippe Aftimos, Mafalda Oliveira, Kevin Punie, Valentina Boni, Erika Hamilton, Ayca Gucalp, Payal Shah, Lida Mina, Priyanka Sharma, Lisa Bauman, Eric Campeau, Sarah Attwell, Margo Snyder, Karen Norek, Akos Czibere, Yanke Yu, Michael H Silverman, Sanjay Lakhotia, Susan Domchek, Jennifer Litton, Mark Robson. A Phase 1b/2 Study of the BET inhibitor ZEN003694 in combination with talazoparib for treatment of patients with TNBC without gBRCA1/2 mutations [abstract]. In: Proceedings of the 2020 San Antonio Breast Cancer Virtual Symposium; 2020 Dec 8-11; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2021;81(4 Suppl):Abstract nr PS11-10.

Background: Angiogenesis plays a substantial role in breast cancer development as well as in triple negative breast cancer (TNBC). Sunitinib is an inhibitor of the tyrosine kinase receptors for VEGF, platelet-derived growth factor (PDGF), KIT, RET, and fms-like tyrosine kinase receptor-3 (FLT3). As monotherapy in heavily pretreated breast cancer patients (pts), sunitinib demonstrated a response rate of 15% in TNBC (11% of all pts) with stable disease or better in 16% of all pts. The combination of paclitaxel and carboplatin is ideally suited for further exploration as neoadjuvant chemotherapy for TNBC, based on the established preclinical and clinical sensitivity of TNBC to these cytotoxic agents. This open label, phase I/II trial was designed to evaluate the combination of sunitinib plus paclitaxel and carboplatin as neoadjuvant treatment for locally advanced breast cancer. The primary objective for the phase I portion was to determine the maximum tolerated dose (MTD); these results are presented. Methods: Women with histologically confirmed invasive triple-negative adenocarcinoma of the breast, (defined as <10% staining by IHC for ER/PR; IHC 0–1+ or FISH negative for HER2), with no evidence of metastatic disease and normal LVEF were eligible. All pts received sunitinib (days 1–28), paclitaxel (days 1, 8, 15), and carboplatin (day 1) in 28-day treatment cycles x6. Following 6 cycles, pts had definitive surgery. After ≥2 weeks and evidence of adequate wound healing, maintenance sunitinib 25mg PO daily was initiated to complete a total of 52 weeks. Three dose levels were evaluated as shown in the table below: Doses were escalated in sequential cohorts of pts using standard phase I methodology. MTD was defined as the highest dose level (DL) producing ≤1 dose limiting toxicities (DLTs) in a pt cohort. The MTD identified in the phase I portion of the study will be used in the phase II portion, which will evaluate the efficacy, safety, and tolerability of this combination in pts with locally advanced TNBC. Results: 15 women with TNBC were enrolled between 10/2009 and 2/2011 [median age 53 years (range: 40–78)]. Due to grade 3 neutropenia resulting in the inability to deliver cycle 1 day 15 paclitaxel in the first pt treated at both DLs 1 and 2, these DLs were expanded to 6 pts each. No additional cycle 1 DLTs were noted in the 5 additional pts at either DL. Three pts were accrued to DL 3; there were 2 DLTs noted among these pts (grade 3 febrile neutropenia; grade 3 neutropenia with cycle 2 day 1 treatment delay). However, due to the development of grade 3/4 neutropenia in subsequent cycles in 5 of 6 DL 2 pts, resulting in dose delays and requiring dose reductions, the MTD of this combination was defined as DL 1 (paclitaxel 70mg/m2 (Days 1, 8, 15); carboplatin AUC=5 (Day 1); sunitinib 25mg PO daily). Conclusions: The administration of sunitinib with paclitaxel plus carboplatin as neoadjuvant therapy is feasible with neutropenia defining the MTD of this combination. The phase II portion of this study is ongoing. Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P3-14-29.

e17594 Background: In the phase III DECISION trial comparing SOR with placebo, pts with advanced RAI-R DTC treated with SOR experienced higher rates of adverse events (AEs) than pts with renal cell carcinoma and hepatocellular carcinoma treated with SOR (Brose et al. Lancet 2014). We hypothesized that long-term thyroxine suppressive therapy might result in a high prevalence of sarcopenia, which is known to be associated with increased toxicity of SOR (Antoun et al. Ann Oncol 2010), and we investigated whether sarcopenia at baseline correlated with DLT. Methods: In DECISION, pts with an analyzable baseline lumbar CT scan were eligible. Skeletal muscle cross-sectional area at the third lumbar vertebra was measured, and the median value for each sex defined the cut-off points for sarcopenia. DLT was defined as any AE leading to dose modification; early toxicities occurred ≤30 days after treatment initiation. Results: Of 365 eligible pts, 199 (55%) were sarcopenic (SOR n = 100, placebo n = 99) with large geographic differences: 65/91 Asians (71%), 29/62 North Americans (47%), and 105/212 Europeans (50%). Sarcopenia was 3-fold more frequent than non-sarcopenia in pts ≥75 years of age (19% vs 6%) and was associated with lower body weight (mean [standard deviation]: 71.3 [16.8] vs 80.8 [19.5]; P < 0.0001). Among SOR pts, 76/180 (42%) experienced early DLT of which 44/76 (58%) occurred in sarcopenic pts (P = 0.6497). Among the 90 males, 61 (68%) were sarcopenic and of the 35 males with early DLT, 27 (77%) were sarcopenic. Median time to DLT in sarcopenic vs non-sarcopenic pts who received SOR was 63 vs 95 days, respectively (log-rank P = 0.5328). Conclusions: In this exploratory analysis from DECISION, approximately half of the pts were sarcopenic. In the overall population, no association between sarcopenia and early DLT or DLT were found. Clinical trial information: NCT00984282.

Phase Ib study of talimogene laherparepvec in combination with atezolizumab in patients with triple negative breast cancer and colorectal cancer with liver metastases

Purpose: HER2+ and triple-negative (TN) breast cancers (BC) are associated with an aggressive course and poor prognosis, with currently available treatments yielding low response rates and decreased progression-free survival (PFS) due to a high relapse rate, rapid disease progression, and development of resistance. Hence, novel agents with efficacy and a tolerable safety profile are needed for this challenging patient (pt) population. Ibrutinib is a first-in-class, oral inhibitor of Bruton's tyrosine kinase (BTK), which is a crucial signaling molecule in the B-cell receptor pathway. It has demonstrated robust clinical activity in B-cell malignancies. In preclinical studies, ibrutinib inhibited tyrosine phosphorylation of ErbB and ErbB2 in HER2- positive BC cell lines, thereby suppressing AKT and MAPK signaling (Elias, 2013; Grabinski, 2014). Programmed death-ligand 1 (PD-L1) is a molecule associated with inhibition of antitumor T cell immunity (Zou, 2008; Keir, 2008), and is highly expressed in TNBC (Tessari, 2014; Mittendorf, 2014). Durvalumab (MEDI4736) is a selective, high-affinity human IgG1 monoclonal antibody that blocks PD-L1 binding to PD-1 (IC50 of 0.1nM) and CD80/B7.1 (IC50 of 0.04 nM) (Ibrahim, 2015). Durvalumab has shown promising clinical activity with an acceptable safety profile across multiple solid tumors (Fury, 2014; Segal, 2014; Antonia, 2014). The combination of an anti–PD-L1 antibody and ibrutinib suppressed tumor growth in mouse models of solid tumors, and led to enhanced antitumor T-cell immune responses (Sagiv-Barfi, 2015). Based on these encouraging preclinical data, the PCYC-1135 trial (NCT02403271) was initiated to test the safety and efficacy of ibrutinib plus durvalumab in pts with relapsed/refractory (R/R) Stage III/IV BC (both HER2+ and TNBC), as well as non-small cell lung cancer (NSCLC), and pancreatic cancer. This abstract focuses on the BC cohort enrolling in the trial. Methods: A total of 130–160 pts (BC, NSCLC, and pancreatic) will be enrolled in this Phase 1b/2 study. Key eligibility criteria for the BC cohort include pathologically confirmed BC (HER2+ or TN), R/R disease (Stage III or IV) failing at least 2 prior therapies, measurable lesion by RECIST 1.1, and adequate hematologic, hepatic, and renal function. Key exclusion criteria include central nervous system involvement, antitumor therapy within 21 days of study initiation, prior treatment with ibrutinib or other BTK inhibitors, and/or anti-PD1, anti–PD-L1, anti–PD-L2, anti–CD137 or anti–CTLA-4 antibody, a history of allogeneic organ transplant, or treatment with a strong cytochrome P4503A inhibitor. The primary objectives are safety, tolerability, and efficacy as assessed by overall response rate. Secondary endpoints are disease control rate, duration of response, PFS, overall survival, and pharmacokinetics and pharmacodynamic assessments of the combination. The Phase 1b will assess dose-limiting toxicities (DLTs) and will determine the recommended phase 2 dose (RP2D) of ibrutinib plus durvalumab. The starting dose level of ibrutinib is 560 mg daily, with the potential for subsequent dose level reductions if DLTs occur, in combination with durvalumab 10 mg/kg IV every 2 weeks in 28-day cycles until DLT or disease progression. Enrollment in phase 2 will commence at the RP2D, accruing a total of 130–160 pts (Phase 1b + Phase 2). Ibrutinib and durvalumab will be administered until unacceptable toxicity or disease progression. Enrollment began in March 2015. Citation Format: Drew W. Rasco, Erkut Borazanci, Martin Guiterrez, David Hong, Ahmed Tawashi, Jennifer Lin, Isaiah W. Dimery, Mark Fosdale. Ibrutinib in combination with durvalumab (MEDI4736) in patients with relapsed or refractory HER2-positive or triple-negative breast cancer: A phase 1b/2 multicenter study. [abstract]. In: Proceedings of the AACR Special Conference on Advances in Breast Cancer Research; Oct 17-20, 2015; Bellevue, WA. Philadelphia (PA): AACR; Mol Cancer Res 2016;14(2_Suppl):Abstract nr B42.

3108 Background: Selinexor (KPT-330) is potent inhibitor of Exportin-1. In vitro, Selinexor was found to be synergistic with eribulin in triple negative breast cancer (TNBC) cell lines and enhanced antitumor activity of eribulin in TNBC patient-derived xenografts (PMID 28810913). Methods: We conducted a phase Ib trial in combination of selinexor and eribulin using 3 + 3 design in dose escalation for patients with advanced solid tumors and in TNBC in dose expansion cohort. Eribulin could be discontinued after combination for 6 cycles at physician discretion. Primary objectives: Safety, Recommended Phase 2 Dose (RP2D). Secondary Objectives: Objective Response Rate (ORR), Duration of Response (DOR), Disease Control Rate (DCR), Overall Survival (OS) and Progression Free Survival (PFS). Results: 31 patients, TNBC (n = 19), sarcoma (n = 8), others (n = 4) enrolled in dose escalation (n = 10) and dose expansion phases (n = 21). Median prior therapies:4 (1–6). Study initiated selinexor at 60mg twice weekly and eribulin 1.4mg/m2 on Day1, Day8 every 3 weeks which led to 1 Dose Limiting Toxicity (DLT) and hence, selinexor 80mg once weekly and eribulin 1mg/m2 was elected as RP2D due to efficacy and tolerability. As of 01/15/2022, of 29 patients (94%) who have discontinued treatment, 24 (77%) were due to progressive disease, 3 (10%) withdrew consent and 2 (6%) due to toxicities (G1 pneumonitis; G3 neutropenia) while 2 (6%) remain on trial. All 31 patients had at least one treatment emergent adverse event (TEAE) while most prevalent TEAEs (all grades) were leukopenia (77%), nausea (71%), anemia and neutropenia (68%) and fatigue (48%). The most common G3/4 TEAE were leukopenia (26%) and neutropenia (29%). 2 DLTs occurred; 1 in first dose level (DL); 1 in second DL dosed at selinexor 80 mg once weekly due to G3 neutropenia. ORR for all was 10% while DCR (SD+PR+CR) > 6 months seen in 3 (15%) TNBC and 2 (20%) sarcoma patients. The median OS and PFS for all were 12.3 (7.3, 27.3) months and 2.3 (1.6, 4.1) months. In dose escalation cohort, ORR was 10% where one patient (3%) with vaginal SCC had confirmed PR (-44%) for 2.1 months. Five patients (62.5%) with sarcoma had stable disease (SD). One patient with high grade sarcoma has SD for 68 months and remains on selinexor after 4 months of eribulin and selinexor. In TNBC dose expansion (n = 19), ORR was 10.5% with 2 confirmed PRs and median duration of response (DOR) of 10.8 months. One patient who has remained on treatment for 18 months, and after receiving 8 months of eribulin and selinexor, remains on selinexor with 100% target regression and an indeterminate brain lesion. Conclusions: Selinexor with eribulin is safe with manageable toxicity profile and modest overall clinical efficacy. Durable responses and disease control were observed with metastatic TNBC. Further study is needed to examine the determinants of response to this combination. Clinical trial information: NCT02419495.

Background: TT-00420, a multikinase inhibitor, targets cell proliferation, angiogenesis, and immunomodulatory pathways by inhibiting the mitotic kinases Aurora A/B, Janus kinases (JAK) involved in cytokine signalling, and receptor tyrosine kinases involved in angiogenesis (FGFRs and VEGFRs). These pathways are important in the pathogenesis of triple negative breast cancer (TNBC) and TT-00420 has shown preclinical efficacy against multiple subtypes of TNBC. Methods: This phase I, open-label, first-in-human study is enrolling adult patients with advanced or metastatic TNBC and other advanced solid tumors. The study contains a dose escalation phase (N=22), followed by dose expansion in two parallel cohorts, a TNBC cohort (N=22) and a selected advanced tumor (SAT) cohort (N=22). The provisional dose range for dose escalation is 1 mg/d to 20 mg/d. Dose escalation is guided by Bayesian modeling with overdose control until a dose recommended for dose expansion is determined. Adverse events (AE) are evaluated per CTCAE v5.0 criteria, and tumor response is evaluated per RECIST v1.1 criteria. Patients receive a single daily oral administration of TT-00420 continuously for 28-day cycles. The primary endpoint is to evaluate dose limiting toxicity (DLT) and identify a maximum tolerated dose (MTD). Secondary objectives include evaluating the efficacy and pharmacokinetic profile of TT-00420. Results: As of the data cut-off date on September 26, 2019, 11 patients have received TT-00420 treatment in 4 dose levels, 1 mg/d (N=1), 3 mg/d (N=1), 5 mg/d (N=3), and 8 mg/d (N=6). No DLTs have been observed at any of the tested dose levels. Commonly reported suspected AEs across all tested dose levels were grades 1 or 2 diarrhea (n=4, 36.4%), myalgia (n=2, 18.2%) and hypertension (n=2, 18.2%). Two suspected serious adverse events reported were grade 2 hypertension (8 mg/d) and grade 3 nausea (5 mg/d). No grade 3 AEs have occurred in more than one subject. Stable disease has been observed in 4 patients, including a metastatic TNBC patient treated at 8 mg/d, who received 9 lines of prior antineoplastic therapy. Per RECIST v1.1 criteria, this TNBC patient had a 21% decrease in target lesions observed on restaging after two cycles of TT-00420 treatment. Interestingly, significant clinical improvement in the skin lesions were observed as well. More detailed data from this TNBC patient and other patients treated in the study will be presented. Enrollment in dose escalation is currently ongoing. Clinical trial information: NCT03654547 Citation Format: Sarina A. Piha-Paul, Ecaterina Ileana-Dumbrava, Filip Janku, Daniel D. Karp, Funda Meric-Bernstam, Jordi Rodon, Brenda Ngo, Peng Peng, Frank Wu. Phase I study of TT-00420, a multiple kinase inhibitor, in patients with triple negative breast cancers and other advanced solid tumors [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 3011.

Background: The epidermal growth factor receptor (EGFR) is frequently overexpressed in triple negative breast cancer (TNBC). However, EGFR inhibitors have not shown efficacy as monotherapy in TNBC. One strategy for overcoming resistance to EGFR inhibition is concomitant inhibition of downstream signaling. Metformin is a LKB1-dependent AMPK activator that inhibits both MAPK and AKT signaling. The combination of the EGFR inhibitor erlotinib and metformin synergistically induces apoptosis in TNBC cell lines and decreases tumor burden in PTEN-null EGFR-amplified mouse xenograft models. We evaluated the combination of erlotinib and metformin in a phase 1 study of patients with advanced TNBC. Methods: Patients with advanced TNBC who had received at least one prior line of therapy for metastatic disease were eligible. Erlotinib dose was fixed at 150mg daily. Metformin dose escalation was planned according to a 3+3 design, beginning at 850mg BID and escalating to 850mg TID. One de-escalation to 500mg BID was allowed. Dose-limiting toxicities (DLT) were assessed during the first five weeks of therapy. The primary objectives were to determine the maximum tolerated dose (MTD) of metformin with fixed dose erlotinib and to determine the potential for clinical benefit. Secondary endpoints were response rate, stable disease rate, and progression free survival. Pre- and on-treatment skin biopsies were collected to determine the effect of the study drugs on their respective cell signaling targets, particularly EGFR, AMPK, and mTOR. Results: Between March 2013 and May 2015, nine patients were screened and eight were enrolled. Median age was 48 years (range 37-79). Median number of prior therapies for metastatic disease was 2.5 (range 1-6). No DLT events were reported in either of the dose escalation cohorts during the DLT assessment period. AEs occurring in three or more patients and all grade III AEs are reported in Table 1. Grade III diarrhea despite maximum supportive care required dose reduction of metformin from 850mg TID to 850mg BID in one patient. Grade III rash led to study withdrawal in one patient. No grade IV AEs were reported. Per RECIST v1.1, the best observed response was stable disease in two patients (25%). Median time on study was 2.0 months (range 1.2-3.0). Skin biopsy marker assessment is ongoing and will be reported. Conclusion: The combination of erlotinib and metformin was generally well tolerated in a population of pre-treated metastatic TNBC patients. No unexpected toxicities occurred. While no responses were achieved, stable disease was observed in patients who received this non-chemotherapy combination. Adverse EventsEventMetformin 850mg BID n=3Metformin 850mg TID n=5All patients n=8 Number of patients (percent) All gradesGrade IIIAll gradesGrade IIIAll gradesGrade IIIRash3 (100)1 (33.3)5 (100)08 (100)1 (12.5)Diarrhea3 (100)05 (100)2 (40.0)8 (100)2 (25.0)Weight loss1 (33.3)05 (100)06 (75.0)0Dry skin1 (33.3)05 (100)06 (75.0)0Nausea2 (66.7)03 (60.0)05 (62.5)0Vomiting1 (33.3)03 (60.0)04 (50.0)0Dry mouth1 (33.3)03 (60.0)04 (50.0)0Dysgeusia1 (33.3)02 (40.0)03 (37.5)0Increased creatinine2 (66.7)01 (20.0)03 (37.5)0Fatigue1 (33.3)02 (40.0)03 (37.5)0Anorexia1 (33.3)02 (40.0)03 (37.5)0Hyponatremia1 (33.3)1 (33.3)001 (12.5)1 (12.5) Citation Format: Fenn KM, Maurer MA, Lee SM, Crew KD, Trivedi MS, Accordino MK, Hershman DL, Kalinsky K. A phase 1 study of erlotinib and metformin in advanced triple negative breast cancer [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P6-18-35.

BACKGROUND: RAD001 is an oral mTOR inhibitor that has exhibited activity in breast cancer. Triple negative breast cancer cells are unable to repair double stranded DNA breaks and hence have sensitivity to platinum agents that cause interstrand cross-links. Rapamycin acts synergistically with platinum agents to induce apoptosis and inhibit proliferation in at least two different breast cancer cell lines (including ER/PR negative cell lines). We propose that combination RAD001 and carboplatin may have activity in triple-negative breast cancer. MATERIALS AND METHODS: The primary objective of the study is to determine clinical benefit (complete remission (CR) + partial remission (PR) + stable disease (SD more than 6 months)) and the toxicity of this combination in triple negative metastatic breast cancer who have had 0–3 prior chemotherapy regimens for metastatic disease. Twenty-five subjects were to be entered in this Phase II study. This design has greater than 80% power to test the null hypothesis that the clinical benefit rate is less than or equal to 10% versus the alternative hypothesis that clinical benefit rate is greater than or equal to 30%. Prior carboplatin is allowed. Women with treated brain metastasis are eligible. Secondary objectives are to determine progression free survival and relationship between pretreatment sensitivity (biopsy at baseline) and clinical response (biopsy post 2 cycles) using IHC staining for abundance of key proteins in the Akt-mTOR pathway and their activity using surrogate phosphorylation site-specific antibodies. According to the original study plan, carboplatin AUC 6, was to be given intravenously every three weeks. Five mg of RAD001 was to be given daily with a 3 patient run-in and then 10 mg daily if there were no dose-limiting toxicities. Due to a surprising amount of thrombocytopenia with this combination the dose of carboplatin was first amended to AUC 5 and most recently to AUC 4 with 5 mg of RAD001 (and no plan to escalate to 10 mg). RESULTS: 23 patients of a planned 25 have been recruited thus far. Median age is 59. Of the 20 patients assessable for response at this time, there have been 1 CR, 5 PRs, 8 SDs and 6 PDs. One SD was achieved in a patient progressing on single agent Carboplatin at study entry. Median duration of CR+ SD +PR thus far is 13 weeks (range: 6–74 weeks). 5 of 22 patients assessable for toxicity had grade 3/4 thrombocytopenia and 4 patients had grade 3 neutropenia (no febrile neutropenia). 13 out of eighteen patients have had treatment held and/or dose reductions secondary to hematological toxicity, however, since amendment for starting dose of Carboplatin to AUC 4 the regimen has been very well tolerated with only 1 out of eleven patients with grade 3 neutropenia and grade 3 thrombocytopenia. 1 patient suffered from grade 3 dehydration. The estimated clinical benefit rate is 45% (95% confidence interval: 23%, 67%). Median time to progression or death is 85 days from start of treatment. CONCLUSIONS: Our study has met the primary end point of demonstrating clinical benefit in triple negative metastatic breast cancer. Dose limiting thrombocytopenia was an unexpected side effect requiring protocol amendment. We continue to accrue study subjects at the amended dosing. Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P5-20-05.